JP2018173765A - Road friction coefficient management device, server device, methods therefor, computer program and recording medium with computer program recorded thereon - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a road friction coefficient management device, a server device, methods therefor, a computer program and a recording medium with the computer program recorded thereon.SOLUTION: A road friction coefficient management device comprises a road information storage part for storing positional information of a road and road information including a reference friction coefficient of the road in an associated manner. Positional information of a probe car is identified, an actual friction coefficient of the probe car in the identified positional information is measured and while referring to the road information storage part, a road corresponding to the identified positional information of the probe car is selected. A reference friction coefficient of the selected road is identified, and a difference between the identified reference friction coefficient and the measured actual friction coefficient is calculated. If an error is equal to or greater than a predetermined threshold as a result of the calculation, a subsequent vehicle of the probe car and/or a server device is notified of the measured actual friction coefficient together with the positional information of the probe car.SELECTED DRAWING: Figure 1

Description

  The present disclosure relates to a road friction coefficient management device and a server device, and a method, a computer program, and a recording medium on which the computer program is recorded.

In recent years, with the development of car navigation technology and the rapid progress of automatic vehicle driving technology, the use of probe information obtained from probe cars has become more important in order to provide more detailed maps and road conditions. .
On the other hand, in both vehicle driving and automatic driving by a driver, it is generally recognized that the road surface condition of the road affects the vehicle control, and grasping the road surface condition leads to an improvement in the safety of vehicle travel. As a technique for estimating the state of a road surface on which a vehicle travels, Patent Document 1 irradiates a laser beam so as to scan the road surface, acquires a reflection intensity value corresponding to each irradiation point on the road surface, A technique for discriminating a road surface state using an intensity value is disclosed.
See also Patent Documents 2 to 7 as related art related to the present disclosure.

JP 2014-228300 A International Publication No. 2013/190637 JP 2008-157760 A JP 2015-215286 A JP 2004-294152 A JP 2003-346286 A JP 2001-82966 A

  The inventors use the probe information obtained from the probe car, and change information related to the road surface condition of the road based on the probe information to the subsequent vehicle or the server device of the probe car more simply and practically. Has been eagerly studied to make it possible. As a result, based on the difference between the measured friction coefficient of the probe car and the reference friction coefficient of the road including the position where the measured friction coefficient is measured, the measured friction coefficient and the measured friction coefficient when the difference is equal to or greater than a predetermined threshold. It has been conceived that the position of the probe car whose coefficient has been measured is notified to the vehicle following the probe car or the server device.

The present disclosure has been made to achieve the above object, and a road friction coefficient management device and a server device according to at least some aspects of the present disclosure are defined as follows.
The road friction coefficient management device defined in the first aspect is
A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A position information specifying unit for specifying the position information of the probe car;
A measurement unit for measuring an actual friction coefficient of the probe car in the specified position information;
With reference to the road information storage unit, a selection unit that selects a road corresponding to the position information of the identified probe car;
Referring to the road information storage unit, a specifying unit for specifying a reference friction coefficient of the selected road;
A computing unit for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is equal to or larger than a predetermined threshold, the notification unit that notifies the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or the server device of the probe car;
Is provided.

According to the road friction coefficient management device of the first aspect thus defined, the actual friction coefficient of the probe car traveling on the road is measured, and the road corresponding to the measured position is determined from the road information storage unit. Selecting, referring to the road information storage unit, specifying the reference friction coefficient of the selected road, calculating the difference between the specified reference friction coefficient and the actually measured friction coefficient, and the result of the calculation When the difference is equal to or larger than a predetermined threshold, the measured actual friction coefficient is notified to the subsequent vehicle and / or the server device of the probe car together with the position information of the probe car.
Here, the friction coefficient of the road surface is a ratio of the friction force acting on the contact surface between the vehicle tire and the road surface and the pressure acting perpendicularly to the contact surface, and the proportional constant at this time is represented by the friction coefficient μ. . In general, the smaller this value, the easier it is to slip on the road surface. The reference friction coefficient is a standard friction coefficient defined in advance based on the road surface type or the like of the road, and the actual friction coefficient is a friction coefficient actually measured in the probe car.
That is, according to the road friction coefficient management device, when the slipperiness on the road surface is different from the standard case, for example, when the road surface is slippery compared to the normal case, it was actually measured by the probe car. Notifying the measured friction coefficient and its position alerts the driver of the following vehicle, and enables vehicle driving in consideration of the notified measured friction coefficient. When the succeeding vehicle is an autonomous driving vehicle, automatic control can be performed in consideration of the actually measured friction coefficient at the position.

In addition to the object described in the first aspect, the road friction coefficient management device defined in the second aspect further reduces the amount of data related to the measured friction coefficient, and the difference between the reference friction coefficient and the measured friction coefficient is For the purpose of managing at least one location above a predetermined threshold in units of voxels, it is defined as follows. That is,
A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A first setting unit for setting a voxel on the road and setting a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient in the set voxel with reference to the road information storage unit;
A position information specifying unit for specifying the position information of the probe car;
A measurement unit for measuring an actual friction coefficient of the probe car in the specified position information;
Of the set voxels, an extraction unit that extracts voxels corresponding to the position information of the specified probe car;
A specifying unit for specifying the voxel reference friction coefficient of the extracted voxels;
A calculation unit for calculating a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold, a notification unit that notifies the measured actual friction coefficient together with the voxel identifier of the extracted voxel to the subsequent vehicle and / or server device of the probe car; ,
A road friction coefficient management device comprising:

  According to the road friction coefficient management apparatus of the second aspect defined as described above, a voxel is set on the road, the reference friction coefficient and the measured friction coefficient are compared in units of voxels, and the notified measured friction coefficient is The corresponding voxel identifier is notified to the following vehicle. If the information on the friction coefficient can be managed in units of voxels in this way, the data amount can be reduced. For example, it is possible to reduce the amount of data by managing the measured friction coefficient by a plurality of probe cars in units of voxels and by managing the position corresponding to the measured friction coefficient by voxels.

In addition to the object described in the first aspect, the server device defined in the third aspect further reduces the amount of data related to the measured friction coefficient, and the difference between the reference friction coefficient and the measured friction coefficient is equal to or greater than a predetermined threshold. For the purpose of managing at least one area as an area, it is defined as follows. That is,
A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
An acquisition unit that acquires probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
A first identifying unit that identifies a reference friction coefficient of a road associated with the acquired probe information with reference to the road information storage unit;
A selection unit that selects probe information in which the measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and the difference between the two is equal to or greater than a first threshold value among the acquired probe information; ,
Based on the position information of the selected probe information, a second specifying unit that specifies a region where the density of the probe information is equal to or greater than a second threshold;
Based on the measured friction coefficient of the probe information included in the specified area, a calculation unit that calculates a partial measured friction coefficient of the specified area;
For the specified region, a setting unit for setting the calculated partial measured friction coefficient,
A server device comprising:

  According to the server device of the third aspect defined in this way, a region where the difference between the reference friction coefficient and the measured friction coefficient is equal to or greater than a predetermined threshold and the probe information is highly dense is specified and included in the region A partial measured friction coefficient is calculated based on the measured friction coefficient as probe information, and the partial measured friction coefficient and the region are managed in association with each other. If the information on the friction coefficient can be managed in units of areas in this way, the data amount can be reduced. Further, since the partially measured friction coefficient is managed for each region, even when such information is provided from the server device to the vehicle, it can be suitably used for driving by the driver or automatic driving.

In addition to the object described in the first aspect, the server device defined in the fourth aspect further considers weather information when measuring the actual friction coefficient by the probe car, and It is prescribed. That is,
A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
The probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information at the time of measuring the actual friction coefficient are associated with the road corresponding to the position information. An acquisition unit to acquire
With reference to the road information storage unit, a setting unit that sets a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and is set in advance on a road associated with the acquired probe information;
A selection unit that selects, from among the acquired probe information, probe information whose actual friction coefficient of the acquired probe information is larger than the set specific friction coefficient and whose difference is equal to or greater than a first threshold; ,
Based on the position information of the selected probe information, a specifying unit that specifies an area where the density of the probe information is equal to or greater than a second threshold;
An estimation unit that estimates the identified area as a travel performance area;
A server device comprising:

  According to the server device of the fourth aspect defined in this way, when the measured friction coefficient by the probe car is acquired together with the weather information at the time of measurement, when comparing the acquired measured friction coefficient and the reference friction coefficient, The specific friction coefficient determined for each weather condition is used for the reference friction coefficient, and the obtained actual friction coefficient is compared with the specific friction coefficient associated with the weather condition corresponding to the weather information when the measured friction coefficient is measured. And the area | region where the density of probe information with a measured friction coefficient higher than a specific friction coefficient more than a 1st threshold value is high is specified, and this area | region is estimated as a driving performance area | region. According to such a server device, by comparing the measured friction coefficient according to the weather condition and the specific friction coefficient, it is possible to specify a region where the vehicle traveling on the road is less slippery in the weather, such information. Can be suitably used for driving by a driver or automatic driving.

The server device defined in the fifth aspect is defined as follows for the purpose of managing the reference friction coefficient attached to the road with reference to the actually measured friction coefficient as probe information in units of voxels. . That is,
A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A first setting unit that sets a voxel on the road and sets a position of the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient of the set voxel with reference to the road information storage unit;
Probe information including position information of the probe car, an actual friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to the occupied area in the three-dimensional space of the probe car is included in the position information. An acquisition unit for acquiring in association with the corresponding road;
Based on the acquired occupation area information of the probe car, an extraction unit that extracts all the voxels that overlap with the occupation area information among the set voxels;
For all the extracted voxels, a replacement unit that replaces the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient;
A server device comprising:

  According to the server device of the fifth aspect defined as described above, the reference friction coefficient attached to the road is managed in units of voxels and measured friction coefficient, and further, the vehicle occupation area (for example, the size of the vehicle) The measured friction coefficient as probe information to the voxel can be influenced.

In addition to the object described in the fifth aspect, the server device defined in the sixth aspect further aims to replace the reference friction coefficient with the actual friction coefficient in consideration of the reliability of the actual friction coefficient, It is defined as follows. That is,
In the server device defined in the fifth aspect,
The replacement unit replaces the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient when the number of probe information in the extracted voxel is a predetermined number or more.
According to the server device of the sixth aspect defined in this way, when the probe information in the voxel is a predetermined number or more, the reference friction coefficient attached to the voxel is replaced with the reference friction coefficient in the voxel. Thereby, the influence of the specific measured friction coefficient in the voxel can be reduced.

The road friction coefficient management method defined in the seventh aspect is
A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A position information specifying unit for specifying position information of the probe car;
A measuring step for measuring an actual friction coefficient of the probe car in the specified position information;
A selection unit that refers to the road information storage unit and selects a road corresponding to the position information of the identified probe car; and
A specifying step of specifying a reference friction coefficient of the selected road with reference to the road information storage unit;
A computing step for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
When the result of the calculation shows that the difference is greater than or equal to a predetermined threshold, the notification unit notifies the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or server device of the probe car. Steps,
Is provided.
According to the road friction coefficient management method of the seventh aspect defined as described above, the same effects as those of the first aspect are achieved.

The road friction coefficient management method defined in the eighth aspect is
A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A first setting unit that sets a voxel on the road, and sets a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient in the set voxel with reference to the road information storage unit;
A position information specifying unit for specifying position information of the probe car;
A measuring step for measuring an actual friction coefficient of the probe car in the specified position information;
An extraction step of extracting a voxel corresponding to the position information of the identified probe car from the set voxels;
A specifying step in which the specifying unit specifies the voxel reference friction coefficient of the extracted voxel;
A calculation step of calculating a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
When the difference is equal to or greater than a predetermined threshold as a result of the calculation, the notification unit notifies the measured actual friction coefficient to the succeeding vehicle and / or server device of the probe car together with the voxel identifier of the extracted voxel. A notification step to
Is provided.
According to the road friction coefficient management method of the eighth aspect defined as described above, the same effects as those of the second aspect are achieved.

The server device control method defined in the ninth aspect is:
A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
An acquisition step in which an acquisition unit acquires probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
A first specifying unit that specifies a reference friction coefficient of a road associated with the acquired probe information with reference to the road information storage unit;
The selection unit selects, from among the acquired probe information, probe information whose measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and whose difference is equal to or greater than a first threshold value. A selection step to
A second specifying step in which a second specifying unit specifies a region in which the density of the probe information is equal to or higher than a second threshold based on the position information of the selected probe information;
A calculating step of calculating a partial measured friction coefficient of the specified region based on the measured friction coefficient of the probe information included in the specified region;
A setting step for setting the calculated partially measured friction coefficient for the specified region;
A method for controlling a server device.
According to the control method of the server device of the ninth aspect defined in this way, there is an effect equivalent to that of the third aspect.

The server device control method defined in the tenth aspect is:
A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
The acquisition unit corresponds to the position information, the probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information when the actual friction coefficient is measured. An acquisition step of acquiring in association with the road to be
A setting unit is configured to refer to the road information storage unit and set a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and that is set in advance on a road associated with the acquired probe information. Steps,
The selection unit selects, from among the acquired probe information, probe information whose measured friction coefficient of the acquired probe information is greater than the set specific friction coefficient and whose difference is equal to or greater than a first threshold value. A selection step to
A specifying step of specifying a region in which the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
An estimating step in which the estimating unit estimates the identified area as a travel performance area;
Is provided.
According to the control method of the server device of the tenth aspect defined as described above, the same effect as that of the fourth aspect can be obtained.

The server device control method defined in the eleventh aspect is:
A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A first setting unit that sets a voxel on the road and sets a position of the voxel in association with the voxel;
A second setting step in which a second setting unit sets a voxel reference friction coefficient of the set voxel with reference to the road information storage unit;
The acquisition unit includes probe information including position information of the probe car, measured friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to an occupied area in the three-dimensional space of the probe car. An acquisition step of acquiring in association with the road corresponding to the position information;
Based on the acquired probe car occupation area information, the extraction unit extracts all the voxels that overlap with the occupation area information from the set voxels, and
A replacement step of replacing, for all the extracted voxels, the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient;
Is provided.
According to the control method of the server device of the eleventh aspect defined in this way, the same effect as that of the fifth aspect can be obtained.

The server device control method defined in the twelfth aspect is:
In the server device control method defined in the eleventh aspect,
In the replacing step, when the number of probe information in the extracted voxel is a predetermined number or more, the voxel reference friction coefficient of the voxel is replaced with the acquired actually measured friction coefficient.
According to the control method of the server device of the twelfth aspect defined in this way, the same effect as that of the sixth aspect is achieved.

The computer program defined in the thirteenth aspect is
A computer program for managing a road friction coefficient, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
Position information specifying means for specifying position information of the probe car;
Measuring means for measuring an actual friction coefficient of the probe car in the specified position information;
Referring to the road information storage means, a selection means for selecting a road corresponding to the position information of the identified probe car;
A specifying means for specifying a reference friction coefficient of the selected road with reference to the road information storage unit;
A computing means for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold value, notification means for notifying the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or server device of the probe car;
To function as.
According to the computer program of the 13th aspect prescribed | regulated in this way, there exists an effect equivalent to a 1st aspect.

The computer program defined in the fourteenth aspect is:
A computer program for managing a road friction coefficient, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
First setting means for setting a voxel on the road and setting a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
Referring to the road information storage means, a second setting means for setting a voxel reference friction coefficient to the set voxel;
Position information specifying means for specifying position information of the probe car;
Measuring means for measuring an actual friction coefficient of the probe car in the specified position information;
An extracting means for extracting a voxel corresponding to the position information of the identified probe car among the set voxels;
Identifying means for identifying the voxel reference friction coefficient of the extracted voxels;
A computing means for computing a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold value, a notification means for notifying the measured vehicle friction coefficient together with the voxel identifier of the extracted voxel to a subsequent vehicle and / or a server device of the probe car;
To function as.
According to the computer program of the 14th aspect prescribed | regulated in this way, there exists an effect equivalent to a 2nd aspect.

The computer program defined in the fifteenth aspect is
A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
Acquisition means for acquiring probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
Referring to the road information storage means, a first specifying means for specifying a reference friction coefficient of a road associated with the acquired probe information;
A selection means for selecting probe information in which the measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and the difference between the two is equal to or greater than a first threshold value among the acquired probe information; ,
Second specifying means for specifying a region where the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
Based on the measured friction coefficient of the probe information included in the specified area, a calculation means for calculating a partial measured friction coefficient of the specified area;
Setting means for setting the calculated partial measured friction coefficient for the specified region,
To function as.
According to the computer program of the 15th aspect prescribed | regulated in this way, there exists an effect equivalent to a 3rd aspect.

The computer program defined in the sixteenth aspect is:
A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
The probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information at the time of measuring the actual friction coefficient are associated with the road corresponding to the position information. Acquisition means for acquiring
Referring to the road information storage means, a setting means for setting a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and is set in advance on a road associated with the acquired probe information;
A selection means for selecting probe information in which the measured friction coefficient of the acquired probe information is greater than the set specific friction coefficient and the difference between the two is equal to or greater than a first threshold among the acquired probe information; ,
Identification means for identifying a region where the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
Estimating means for estimating the identified area as a travel performance area,
To function as.
According to the computer program of the 16th aspect prescribed | regulated in this way, there exists an effect equivalent to a 4th aspect.

The computer program defined in the seventeenth aspect is:
A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
A first setting means for setting a voxel on the road and setting a position of the voxel in association with the voxel;
A second setting means for setting a voxel reference friction coefficient of the set voxel with reference to the road information storage means;
Probe information including position information of the probe car, an actual friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to the occupied area in the three-dimensional space of the probe car is included in the position information. An acquisition means for acquiring in association with a corresponding road;
Based on the acquired occupation area information of the probe car, an extraction means for extracting all the voxels that overlap with the occupation area information among the set voxels;
For all the extracted voxels, replacement means for replacing the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient,
To function as.
According to the computer program of the 17th aspect prescribed | regulated in this way, there exists an effect equivalent to a 5th aspect.

The computer program defined in the eighteenth aspect is:
In the computer program defined in the seventeenth aspect,
The replacement means replaces the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient when the number of probe information in the extracted voxel is a predetermined number or more.
According to the computer program of the 18th aspect prescribed | regulated in this way, there exists an effect equivalent to a 6th aspect.

  A recording medium for recording the computer program defined in any of the thirteenth to eighteenth aspects is defined in the nineteenth aspect.

FIG. 1 is a block diagram schematically showing the configuration of a road friction coefficient management device 1 according to the first embodiment of the present invention. FIG. 2 is a flowchart showing an example of a road friction coefficient management method implemented by the road friction coefficient management apparatus 1 according to the first embodiment of the present invention. FIG. 3 is a block diagram schematically showing the configuration of the road friction coefficient management device 21 according to the second embodiment of the present invention. FIG. 4 is a block diagram schematically showing the configuration of the server device 31 according to the third embodiment of the present invention. FIG. 5 is a block diagram schematically showing the configuration of the server device 41 according to the fourth embodiment of the present invention. FIG. 6 is a block diagram schematically showing the configuration of the server device 51 according to the fifth embodiment of the present invention. FIG. 7 is an explanatory diagram for explaining an example of (A) vehicle occupation area information stored in the probe information storage unit and (B) extraction processing in the server device according to the fifth embodiment of the present invention. . FIG. 8 is a block diagram schematically showing the configuration of the road friction coefficient management device 61 according to the first embodiment of the present invention.

  Several embodiments and examples according to the present disclosure will be described below with reference to the accompanying drawings.

<First Embodiment>
FIG. 1 is a block diagram schematically showing a configuration of a road friction coefficient management device 1 as an embodiment of the present invention.
As shown in FIG. 1, the road friction coefficient management device 1 according to the first embodiment includes a map database 3, a road information storage unit 4, a position information specifying unit 5, a measuring unit 7, a selecting unit 9, a specifying unit 11, and a calculation unit. 13 and a notification unit 15.

  The map database 3 stores map data. The map data includes information on road elements for defining map information such as links and nodes, information drawn on a three-dimensional map such as structures, and the like. The map data may be stored as point cloud data or image data from a laser scanner, for example. The map database 3 includes a road information storage unit 4.

  The road information storage unit 4 stores road position information and road information including a reference friction coefficient of the road in association with each other. As the reference friction coefficient, a standard value calculated based on the road surface type is stored. Examples of the road surface type include road surface materials (such as asphalt). The road information may include link information that defines the road and the characteristics of the road, and node information that defines the intersection and the characteristics of the intersection. The road position information and the reference friction coefficient are one of the link information. It can be stored as a part. That is, as link information, in addition to link coordinates as position information, reference friction coefficient, road type, route number, link length, vehicle weight restriction presence / absence, vehicle height restriction presence / absence, number of lanes, road width, speed limit, etc. A travel regulation etc. can be mentioned. The node information includes node coordinates, node type, number of connected links, presence / absence of signals, and the like.

The position information specifying unit 5 specifies position information of the probe car P including the road friction coefficient management device 1. The position information can be specified by a GPS device or a gyro device included in the probe car P. In addition, the current time can be specified.
The measuring unit 7 measures the measured friction coefficient μp of the probe car P in the position information specified by the position information specifying unit 5. The measurement method is not particularly limited as long as it can measure the coefficient of friction between the wheel of the probe car traveling on the road and the road surface of the road. For example, the coefficient of friction of the road surface can be measured. Can be measured with various instruments. As another example, the measured friction coefficient is estimated based on the slip ratio estimated based on the vehicle speed of the probe car and the rotation speed of the driving wheel of the probe car, and the torque acting on the driving wheel. It can also be a value. As yet another example, an actual friction coefficient obtained as probe information of a probe car can be used. When the actual friction coefficient obtained as the probe information is used as the actual friction coefficient in the measurement unit 7, the position information specifying unit 5 stores the position information of the probe car P associated with the actual friction coefficient as the probe information. It can be used as specified location information.

The selection unit 9 refers to the road information storage unit 4 and selects a road corresponding to the position information of the probe car P specified by the position information specifying unit 5. As the selection method, the road on which the probe car P is located can be selected based on the road position information.
The specifying unit 11 refers to the road information storage unit 4 and specifies the reference friction coefficient μs of the road selected by the selection unit 9. Specifically, the road information storage unit 4 can specify the reference friction coefficient associated with the selected road as the reference friction coefficient μs.
The calculating unit 13 calculates a difference D between the reference friction coefficient μs specified by the specifying unit 11 and the actually measured friction coefficient μp measured by the measuring unit 7.

  When the difference D is equal to or greater than a predetermined threshold as a result of the calculation by the calculation unit 13, the notification unit 15 uses the actual friction coefficient μp measured by the measurement unit 7 together with the position information of the probe car P, or the vehicle following the probe car P or Notify server device or both. Here, the predetermined threshold value regarding the difference D can be set to a predetermined value (for example, 0.2) in consideration of the influence on the vehicle driving. As another example, the predetermined threshold value regarding the difference D may be a value corresponding to a predetermined ratio (for example, 20%) of the reference friction coefficient μs of the selected road. Further, the vehicle following the probe car P can be identified by a device that can identify the vehicle following the probe car P. As such a device, for example, an in-vehicle camera, a laser scanner, and inter-vehicle communication are possible. A communication apparatus etc. are mentioned. As another example, you may specify based on the positional information and advancing direction information as probe information of the following probe car. The following vehicle specified by these methods is not limited to one vehicle that immediately follows the probe car P, and may be a plurality of following vehicles located within a predetermined range behind the probe car P. As the information to be notified, the difference D calculated by the calculation unit 13 may be notified together with or instead of the actually measured friction coefficient μp.

FIG. 2 is a flowchart showing an example of a road friction coefficient management method implemented by the road friction coefficient management apparatus 1 shown in FIG.
In step 1, the position information specifying unit 5 specifies position information of an arbitrary probe car P including the road friction coefficient management device 1. In this example, the position information is specified by the GPS device provided in the probe car P.
In step 3, the measurement unit 7 measures the measured friction coefficient μp at the position of the probe car P specified in step 1. In this example, the measured friction coefficient μp is measured by a device equipped with the probe car P that can measure the friction coefficient of the road surface.

In step 5, the selection unit 9 refers to the road information storage unit 4 and selects a road corresponding to the position of the probe car P specified in step 1. In this example, the road associated with the position information including the position information of the probe car P is selected from the roads stored in the road information storage unit 4.
In step 7, the specifying unit 11 specifies the reference friction coefficient μs of the road selected in step 5 with reference to the road information storage unit 4. In this example, the road information storage unit 4 specifies the reference friction coefficient associated with the selected road as the reference friction coefficient μs of the road.

In step 9, the calculation unit 13 calculates a difference D between the actual friction coefficient μp measured in step 3 and the reference friction coefficient μs specified in step 7. As a result of the calculation, when the difference D is equal to or greater than a predetermined threshold (step 11: Yes), the process proceeds to step 13.
In step 13, the notification unit 15 notifies the server device of the position of the probe car P specified in step 1 and the actually measured friction coefficient μp measured in step 3.
In the present embodiment, the position of the probe car notified to the server device and the measured friction coefficient at the position are used to provide information to the following vehicle located behind the probe car P and the vehicle heading to the position of the probe car. Can do. The vehicle that has received such information can perform vehicle control in consideration of the received actual friction coefficient by the driver or by automatic driving.

Second Embodiment
FIG. 3 is a block diagram schematically showing the configuration of the road friction coefficient management device 21 as an embodiment of the present invention.
As shown in FIG. 3, the road friction coefficient management device 21 according to the second embodiment includes a map database 3, a road information storage unit 4, a position information specifying unit 5, a measurement unit 7, a first setting unit 23, and a voxel storage unit. 24, the 2nd setting part 25, the extraction part 26, the specific | specification part 27, the calculating part 28, and the notification part 29 are provided. 3, the same components as those in FIG. 1 are denoted by the same reference numerals, and the description thereof is partially omitted.

  The first setting unit 23 sets a voxel on the road stored in the road information storage unit 4 and sets a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel. The setting method is not particularly limited, and is formed by an arbitrary road stored in the road information storage unit 4 based on the road information stored in the road information storage unit 4 and the map data stored in the map database 3. An area or space to be divided can be divided into predetermined sizes, and each of the divided areas or spaces can be set as voxels. Two-dimensional coordinates or three-dimensional coordinates as position information can be associated with the set voxel. The voxel can be set, for example, as a plane or a cube having sides of 20 cm to 1 m. The shape of the voxel is not limited to a square or a cube, but may be a rectangle or a rectangular parallelepiped. As another example, the first setting unit 23 is a sub-region or sub-space obtained by dividing the region or space for each processing unit, and a sub-region associated with two-dimensional coordinates or three-dimensional coordinates. Alternatively, the subspace may be divided into a predetermined size, and each of the divided spaces may be set as a voxel. The positional information associated with the voxels set in this way may be information indicating the positional relationship between voxels in the sub-region or sub-space in addition to the two-dimensional coordinates or the three-dimensional coordinates. In this case, based on the two-dimensional coordinates associated with the sub-region or the three-dimensional coordinates associated with the sub-space and the information indicating the positional relationship between the voxels, the two-dimensional coordinates in the two-dimensional region or the tertiary in the three-dimensional space. The original coordinates can be calculated. The partitioning process into the sub-region or sub-space may be executed by the first setting unit 23 or may be executed by another processing unit (not shown). A voxel identifier for identifying each voxel is set in the set voxel. The set voxel is stored in the voxel storage unit 24 in association with the position of the voxel and the voxel identifier.

The second setting unit 25 refers to the road information storage unit 4 and the voxel storage unit 24 and sets the voxel reference friction coefficient to the voxel set by the first setting unit 23. Although the setting method is not particularly limited, the reference friction coefficient associated with the road corresponding to the set voxel position can be set as the voxel reference friction coefficient of the voxel. The set voxel reference friction coefficient is stored in the voxel storage unit 24 in association with the corresponding voxel.
The extraction unit 26 refers to the voxel storage unit 24 and extracts a voxel corresponding to the position information of the probe car P specified by the position information specifying unit 5 from the voxels set by the first setting unit 23. As the extraction method, the voxel where the probe car P is located can be extracted based on the position information of the voxel.

The specifying unit 27 refers to the voxel storage unit 24 and specifies the voxel reference friction coefficient of the voxel extracted by the extracting unit 26. The specific method is not particularly limited, but based on the voxel reference friction coefficient set by the second setting unit 25 stored in the voxel storage unit 24, the voxel reference friction coefficient of the voxel corresponding to the extracted voxel. Can be identified as the voxel reference friction coefficient of the extracted voxels.
The calculating unit 28 calculates the difference between the voxel reference friction coefficient specified by the specifying unit 27 and the actually measured friction coefficient measured by the measuring unit 7.
When the difference is equal to or greater than a predetermined threshold as a result of the calculation by the calculation unit 28, the notification unit 29 includes the actual friction coefficient measured by the measurement unit 7 together with the voxel identifier of the voxel extracted by the extraction unit 26. Notify the following vehicle or the server device or both.

<Third Embodiment>
FIG. 4 is a block diagram schematically showing the configuration of the server device 31 as an embodiment of the present invention.
As shown in FIG. 4, the server device 31 of the fourth embodiment includes a map database 3, a road information storage unit 4, a probe information storage unit 32, an acquisition unit 33, a first specification unit 34, a selection unit 35, and a second unit. The specifying unit 36, the calculation unit 37, and the setting unit 38 are provided. 4, the same components as those in FIGS. 1 and 3 are denoted by the same reference numerals, and description thereof is partially omitted.

  The probe information storage unit 32 stores vehicle probe information. The probe information includes at least coordinate information as position information, time information, and a friction coefficient (μ: friction force acting on a contact surface between a tire and a road surface). The coordinate information includes two-dimensional or three-dimensional coordinate information. If the vehicle has a position detection function such as GPS, these pieces of information can be specified. Other information included in the probe information includes, for example, information related to a vehicle ID for identifying a probe car, direction, speed, acceleration, brake, sudden brake, turn signal, steering angle, headlight, wiper, and the like. It is done.

The acquisition unit 33 refers to the road information storage unit 4 and the probe information storage unit 32, and obtains probe information including the position information of the probe car and the actual friction coefficient measured at the position corresponding to the position information. Acquired in association with the road corresponding to the position information. As the acquisition method, based on the position information of the road, the probe information stored on the road out of the probe information stored in the probe information storage unit 32, together with the measured friction coefficient measured at the position, Acquired in association with the road.
The first specifying unit 34 refers to the road information storage unit 4 and specifies the reference friction coefficient of the road associated with the probe information acquired by the acquisition unit 33. As the specific method, with respect to the road acquired in association with the probe information by the acquisition unit 33, the reference friction coefficient associated with the road is specified with reference to the road information storage unit 4.

In the probe information acquired by the acquisition unit 33, the selection unit 35 has a measured friction coefficient of the acquired probe information smaller than the reference friction coefficient specified by the first specification unit 34, and the difference between the two is the first. Probe information that is equal to or greater than a threshold value of 1 is selected. As the selection method, for example, probe information whose measured friction coefficient is smaller than the reference friction coefficient by a first threshold or more (for example, 0.2 or more) can be selected.
The second identification unit 36 identifies the position information of the selected probe information with reference to the acquisition unit 33 with respect to the probe information selected by the selection unit 35, and the density of the probe information is a second threshold value. The area which is the above is specified. The specific method is not particularly limited. For example, the density can be the number of the selected probe information per unit area (for example, 50 cm square), and the number is equal to or greater than a second threshold ( For example, a region that is 5 or more) can be specified.

The computing unit 37 computes a partially measured friction coefficient of the specified region based on the actually measured friction coefficient of the probe information included in the region specified by the second specifying unit 36. The calculation method is not particularly limited. For example, the measured friction coefficient of the probe information in the region may be averaged, or the lowest value among the measured friction coefficients of the probe information in the region may be used. Good.
The setting unit 38 sets the partially measured friction coefficient calculated by the calculation unit 37 for the region specified by the second specifying unit. The set partial measured friction coefficient may be stored in the storage unit (not shown) together with the position information of the region corresponding to the partial measured friction coefficient, or the corresponding link in the road information storage unit 4 It is good also as saving in relation to.

<Fourth embodiment>
FIG. 5 is a block diagram schematically showing the configuration of the server device 41 as an embodiment of the present invention.
As illustrated in FIG. 5, the server device 41 according to the fourth embodiment includes a map database 3, a road information storage unit 4, a probe information storage unit 32, an acquisition unit 43, a setting unit 44, a selection unit 45, a specification unit 46, and an estimation. The unit 47 is provided. In FIG. 5, the same components as those in FIGS. 1, 3, and 4 are denoted by the same reference numerals, and description thereof is partially omitted.

  The road information storage unit 4 further stores a specific friction coefficient for each weather condition with respect to the reference friction coefficient associated with the road. The specific friction coefficient is calculated, for example, by multiplying the reference friction coefficient by a coefficient determined in advance corresponding to weather conditions. Specifically, a table or the like associated with the coefficients “0.8”, “0.6”, “0.4” corresponding to the weather conditions “rain”, “snow”, “freezing”, etc., respectively. For the reference friction coefficient “0.8”, when the weather condition is “rain”, the reference friction coefficient “0.8” is multiplied by the coefficient “0.8” corresponding to the weather condition “rain”. Specific friction coefficient. The specific friction coefficient of each weather condition obtained in this way is stored in association with the corresponding reference friction coefficient. In this example, the reference friction coefficient “0.8” is “0.64” when the weather condition is “rain”, “0.48” when “snow”, and “0.32” when “freezing”. A specific coefficient of friction such as The weather conditions are not limited to the above-described conditions, and may be based on precipitation, temperature, or a combination thereof.

In the probe information storage unit 32, in addition to the probe information including the position information of the probe car and the actual friction coefficient measured at the position indicated by the position information, the weather when the actual friction coefficient is measured is further included. Information is stored in association with probe information. Examples of the weather information include weather information such as rain, snow, freezing, precipitation information, temperature information, or a combination thereof.
The acquisition unit 43 refers to the road information storage unit 4 and the probe information storage unit 32, and includes probe information including the position information of the probe car and the actually measured friction coefficient measured at the position indicated by the position information, Weather information at the time of measuring the measured friction coefficient is acquired in association with the road corresponding to the position information. The acquisition method can be performed by the same method as the acquisition unit 33.

The setting unit 44 refers to the road information storage unit 4 and applies a specific friction coefficient associated with the weather condition corresponding to the weather information to the road associated with the probe information acquired by the acquisition unit 43 in advance. Set a specific coefficient of friction. The setting method is not particularly limited. For example, for a road acquired by the acquisition unit 43, if the weather information when the measured friction coefficient of the road is measured is "rain", the road A specific friction coefficient “0.64” when the associated weather condition is “rain” is set.
In the probe information acquired by the acquisition unit 43, the selection unit 45 has a measured friction coefficient of the acquired probe information larger than the specific friction coefficient set by the setting unit 44, and the difference between the two is a first threshold value. The probe information as described above is selected. As the selection method, for example, probe information whose measured friction coefficient is larger than the specific friction coefficient by a first threshold or more (for example, 0.1 or more) can be selected.

Based on the position information of the probe information selected by the selection unit 45, the specifying unit 46 specifies a region where the density of the probe information is equal to or greater than the second threshold. Although the said specific method is not specifically limited, It can carry out by the method similar to the 2nd specific | specification part 36. FIG.
The estimation unit 47 estimates the region specified by the specifying unit 46 as a travel performance region. The estimated area can be stored in association with a corresponding link in the road information storage unit 4, for example.
Since the travel performance area estimated in this way is an area that is less slippery than other parts of the road under the weather conditions, the vehicle control is supported by notifying the vehicle traveling on the road Yes.

<Fifth Embodiment>
FIG. 6 is a block diagram schematically showing the configuration of the server device 51 as an embodiment of the present invention.
As shown in FIG. 6, the server device 51 of the fifth embodiment includes a map database 3, a road information storage unit 4, a probe information storage unit 32, a first setting unit 23, a voxel storage unit 24, and a second setting unit. 25, an acquisition unit 53, an extraction unit 54, and a replacement unit 55. In FIG. 6, the same components as those in FIGS. 1, 3, 4, and 5 are denoted by the same reference numerals, and description thereof is partially omitted.

  The probe information storage unit 32 corresponds to the probe information including the position information of the probe car and the measured friction coefficient measured at the position corresponding to the position information, and further corresponds to the occupied area in the three-dimensional space of the probe car. Occupied area information is stored in association with probe information. The occupied area information of the probe car includes the vehicle width, the vehicle height, and the total length of the probe car. The occupation area information may include the information itself as probe information, or may be calculated based on the vehicle type when the vehicle information is included as probe information. The occupied area information is preferably based on the position of the GPS device included in the probe car in the probe car. As shown in FIG. 7A, when the vehicle width and total length of the vehicle A as a probe car are 2.0 m and 5.0 m, respectively, and the GPS device is provided at the point X, the probe car A is occupied. The area information is stored such that the vehicle width is “right width 1.0 m, left width 1.0 m” and the total length is “front 2.0 m, rear 3.0 m” with respect to the point X.

  The acquisition unit 53 obtains probe information including position information of the probe car, an actually measured friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to the occupied area in the three-dimensional space of the probe car. , And obtain it in association with the road corresponding to the position information. The acquisition method can be performed in the same manner as the acquisition unit 33.

The extracting unit 54 refers to the voxel storage unit 24 and, based on the occupied area information of the probe car acquired by the acquiring unit 53, all of the voxels set by the first setting unit that overlap with the occupied area information. Extract voxels. For example, as shown in FIG. 7B, when a voxel having a side of 0.5 m shown by voxels 1 to 66 is set, the extraction unit 54 includes a voxel corresponding to the position of the probe car (vehicle A), That is, not only the voxel 28 corresponding to the position information indicated by the GPS device is extracted, but also the voxels 2-6, 8-12, 14-18, 20-20 overlapping with the occupied area information of the probe car (vehicle A). 24, 26-30, 32-36, 38-42, 44-48, 50-54, 56-60, 62-66 are extracted, respectively. As another example, it is good also as extracting all the voxels which overlap in the width direction on the basis of the position of a GPS apparatus, using a vehicle width as occupation area information. In this case, the extraction unit 54 extracts the voxels 26 to 30. Also, when extracting each voxel, a flag is added so that the voxel extracted based on the position of the GPS device and the voxel extracted based on the occupied area information excluding the position of the GPS device can be identified. It may be left.
The replacement unit 55 replaces the voxel reference friction coefficient of the voxel stored in the voxel storage unit 24 with the actually measured friction coefficient acquired by the acquisition unit 53 for all the voxels extracted by the extraction unit 54.

<First embodiment>
FIG. 8 is a block diagram schematically showing a configuration of a road friction coefficient management device 61 as an embodiment of the present invention. The road friction coefficient management device 61 of the first example includes a control unit 610, a memory unit 611, an input unit 612, an output unit 613, in addition to the constituent elements constituting the road friction coefficient management device 1 of the first embodiment. A following vehicle specifying unit 614, an interface unit 615, and a communication unit 616 are provided. 8, the same components as those in FIGS. 1, 3, 4, 5, and 6 are denoted by the same reference numerals, and the description thereof is partially omitted.

The control unit 610 is a computer device including a buffer memory and other devices, and controls other components constituting the road friction coefficient management device 61.
A computer program is stored in the memory unit 611, and this computer program is read into the control unit 610, which is a computer device, and causes it to function. This computer program can be stored in a general-purpose medium such as an SD (registered trademark) memory card.

The input unit 612 is used, for example, to input a command from a road friction coefficient management device user. As the input unit 612, a pointing device such as a touch panel or a voice input device such as a keyboard or a microphone that cooperates with display contents of a mouse, a light pen, or a display can be used.
The output unit 613 includes a display, a three-dimensional map drawn based on the map database 3, an actual friction coefficient measured by the measurement unit 7, a reference friction coefficient specified by the specification unit 11, and calculated by the calculation unit 13. Information on the difference between the measured friction coefficient and the reference friction coefficient is displayed. In addition, on the side where information on the road friction coefficient is provided from another vehicle, the output unit 613 can display the road and / or position where the actual friction coefficient is measured in addition to the above information. The output unit 613 may include a voice transmission unit and output the information by voice.

  The subsequent vehicle specifying unit 614 specifies a subsequent vehicle that follows the vehicle on which the road friction coefficient management device 61 is mounted. The identification of the succeeding vehicle can be executed based on, for example, a vehicle-mounted camera, a laser scanner, a communication device capable of inter-vehicle communication, and the like. As another example, you may specify based on the positional information and the advancing direction information as probe information of the following vehicle. The succeeding vehicle specified by these methods is not limited to the one immediately following the vehicle on which the road friction coefficient management device 61 is mounted, but is a plurality of succeeding vehicles located within a predetermined range behind the carousel. May be.

The interface unit 615 connects the road friction coefficient management device 61 to a wireless network or the like.
The communication unit 616 enables transmission of the information to the subsequent vehicle specified by the subsequent vehicle specifying unit 614.

  As mentioned above, although embodiment and the Example of this indication were described, this invention is not limited to description of each aspect of the said indication, embodiment (Example), or its modification. Various modifications are also included in the present invention as long as those skilled in the art can easily conceive without departing from the scope of the claims. That is, the present invention modifies the above-described embodiment (example), or combines two or more embodiments (examples) of the above-described embodiments (examples) to form one embodiment (example). Example) is partially implemented, and further includes a mode in which two or more embodiments (examples) are partially combined.

  In this specification, expressions such as “comprising”, “including”, or “having” one element are not exclusive expressions intended to exclude the presence of other elements, It is intended to include components.

1 21 61 Road friction coefficient management device 3 Map database (Map DB)
4 Road information storage unit 5 Location information identification unit 7 Measurement unit 9 35 45 Selection unit 11 27 34 36 46 Identification unit 13 28 37 Calculation unit 15 29 Notification unit 23 25 38 44 Setting unit 24 Voxel storage unit 26 54 Extraction unit 31 41 51 Server device 32 Probe information storage unit 33 43 53 Acquisition unit 47 Estimation unit 55 Replacement unit

Claims (19)

A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A position information specifying unit for specifying the position information of the probe car;
A measurement unit for measuring an actual friction coefficient of the probe car in the specified position information;
With reference to the road information storage unit, a selection unit that selects a road corresponding to the position information of the identified probe car;
Referring to the road information storage unit, a specifying unit for specifying a reference friction coefficient of the selected road;
A computing unit for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is equal to or larger than a predetermined threshold, the notification unit that notifies the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or the server device of the probe car;
A road friction coefficient management device comprising: A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A first setting unit for setting a voxel on the road and setting a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient in the set voxel with reference to the road information storage unit;
A position information specifying unit for specifying the position information of the probe car;
A measurement unit for measuring an actual friction coefficient of the probe car in the specified position information;
Of the set voxels, an extraction unit that extracts voxels corresponding to the position information of the specified probe car;
A specifying unit for specifying the voxel reference friction coefficient of the extracted voxels;
A calculation unit for calculating a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold, a notification unit that notifies the measured actual friction coefficient together with the voxel identifier of the extracted voxel to the subsequent vehicle and / or server device of the probe car; ,
A road friction coefficient management device comprising: A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
An acquisition unit that acquires probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
A first identifying unit that identifies a reference friction coefficient of a road associated with the acquired probe information with reference to the road information storage unit;
A selection unit that selects probe information in which the measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and the difference between the two is equal to or greater than a first threshold value among the acquired probe information; ,
Based on the position information of the selected probe information, a second specifying unit that specifies a region where the density of the probe information is equal to or greater than a second threshold;
Based on the measured friction coefficient of the probe information included in the specified area, a calculation unit that calculates a partial measured friction coefficient of the specified area;
For the specified region, a setting unit for setting the calculated partial measured friction coefficient,
A server device comprising: A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
The probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information at the time of measuring the actual friction coefficient are associated with the road corresponding to the position information. An acquisition unit to acquire
With reference to the road information storage unit, a setting unit that sets a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and is set in advance on a road associated with the acquired probe information;
A selection unit that selects, from among the acquired probe information, probe information whose actual friction coefficient of the acquired probe information is larger than the set specific friction coefficient and whose difference is equal to or greater than a first threshold; ,
Based on the position information of the selected probe information, a specifying unit that specifies an area where the density of the probe information is equal to or greater than a second threshold;
An estimation unit that estimates the identified area as a travel performance area;
A server device comprising: A road information storage unit that associates and stores road position information and road information including a reference friction coefficient of the road;
A first setting unit that sets a voxel on the road and sets a position of the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient of the set voxel with reference to the road information storage unit;
Probe information including position information of the probe car, an actual friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to the occupied area in the three-dimensional space of the probe car is included in the position information. An acquisition unit for acquiring in association with the corresponding road;
Based on the acquired occupation area information of the probe car, an extraction unit that extracts all the voxels that overlap with the occupation area information among the set voxels;
For all the extracted voxels, a replacement unit that replaces the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient;
A server device comprising: The replacement unit replaces the voxel reference friction coefficient of the voxel with the acquired actual measured friction coefficient when the number of probe information in the extracted voxel is a predetermined number or more.
The server device according to claim 5. A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A position information specifying unit for specifying position information of the probe car;
A measuring step for measuring an actual friction coefficient of the probe car in the specified position information;
A selection unit that refers to the road information storage unit and selects a road corresponding to the position information of the identified probe car; and
A specifying step of specifying a reference friction coefficient of the selected road with reference to the road information storage unit;
A computing step for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
When the result of the calculation shows that the difference is greater than or equal to a predetermined threshold, the notification unit notifies the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or server device of the probe car. Steps,
A road friction coefficient management method comprising: A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A first setting unit that sets a voxel on the road, and sets a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
A second setting unit that sets a voxel reference friction coefficient in the set voxel with reference to the road information storage unit;
A position information specifying unit for specifying position information of the probe car;
A measuring step for measuring an actual friction coefficient of the probe car in the specified position information;
An extraction step of extracting a voxel corresponding to the position information of the identified probe car from the set voxels;
A specifying step in which the specifying unit specifies the voxel reference friction coefficient of the extracted voxel;
A calculation step of calculating a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
When the difference is equal to or greater than a predetermined threshold as a result of the calculation, the notification unit notifies the measured actual friction coefficient to the succeeding vehicle and / or server device of the probe car together with the voxel identifier of the extracted voxel. A notification step to
A road friction coefficient management method comprising: A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
An acquisition step in which an acquisition unit acquires probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
A first specifying unit that specifies a reference friction coefficient of a road associated with the acquired probe information with reference to the road information storage unit;
The selection unit selects, from among the acquired probe information, probe information whose measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and whose difference is equal to or greater than a first threshold value. A selection step to
A second specifying step in which a second specifying unit specifies a region in which the density of the probe information is equal to or higher than a second threshold based on the position information of the selected probe information;
A calculating step of calculating a partial measured friction coefficient of the specified region based on the measured friction coefficient of the probe information included in the specified region;
A setting step for setting the calculated partially measured friction coefficient for the specified region;
A method for controlling a server device. A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
The acquisition unit corresponds to the position information, the probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information when the actual friction coefficient is measured. An acquisition step of acquiring in association with the road to be
A setting unit is configured to refer to the road information storage unit and set a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and that is set in advance on a road associated with the acquired probe information. Steps,
The selection unit selects, from among the acquired probe information, probe information whose measured friction coefficient of the acquired probe information is greater than the set specific friction coefficient and whose difference is equal to or greater than a first threshold value. A selection step to
A specifying step of specifying a region in which the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
An estimating step in which the estimating unit estimates the identified area as a travel performance area;
A method for controlling a server device. A road information storage step for storing the road position information and road information including a reference friction coefficient of the road in a road information storage unit in association with each other;
A first setting unit that sets a voxel on the road and sets a position of the voxel in association with the voxel;
A second setting step in which a second setting unit sets a voxel reference friction coefficient of the set voxel with reference to the road information storage unit;
The acquisition unit includes probe information including position information of the probe car, measured friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to an occupied area in the three-dimensional space of the probe car. An acquisition step of acquiring in association with the road corresponding to the position information;
Based on the acquired probe car occupation area information, the extraction unit extracts all the voxels that overlap with the occupation area information from the set voxels, and
A replacement step of replacing, for all the extracted voxels, the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient;
A method for controlling a server device. In the replacing step, when the number of probe information in the extracted voxel is a predetermined number or more, the voxel reference friction coefficient of the voxel is replaced with the acquired actually measured friction coefficient.
The method for controlling a server device according to claim 11. A computer program for managing a road friction coefficient, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
Position information specifying means for specifying position information of the probe car;
Measuring means for measuring an actual friction coefficient of the probe car in the specified position information;
Referring to the road information storage means, a selection means for selecting a road corresponding to the position information of the identified probe car;
A specifying means for specifying a reference friction coefficient of the selected road with reference to the road information storage unit;
A computing means for computing a difference between the identified reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold value, notification means for notifying the measured vehicle friction coefficient together with the position information of the probe car to the subsequent vehicle and / or server device of the probe car;
As a computer program. A computer program for managing a road friction coefficient, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
First setting means for setting a voxel on the road and setting a position of the voxel and a voxel identifier for identifying the voxel in association with the voxel;
Referring to the road information storage means, a second setting means for setting a voxel reference friction coefficient to the set voxel;
Position information specifying means for specifying position information of the probe car;
Measuring means for measuring an actual friction coefficient of the probe car in the specified position information;
An extracting means for extracting a voxel corresponding to the position information of the identified probe car among the set voxels;
Identifying means for identifying the voxel reference friction coefficient of the extracted voxels;
A computing means for computing a difference between the specified voxel reference friction coefficient and the measured actual friction coefficient;
As a result of the calculation, when the difference is greater than or equal to a predetermined threshold value, a notification means for notifying the measured vehicle friction coefficient together with the voxel identifier of the extracted voxel to a subsequent vehicle and / or a server device of the probe car;
As a computer program. A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
Acquisition means for acquiring probe information including position information of the probe car and an actual friction coefficient measured at a position corresponding to the position information in association with a road corresponding to the position information;
Referring to the road information storage means, a first specifying means for specifying a reference friction coefficient of a road associated with the acquired probe information;
A selection means for selecting probe information in which the measured friction coefficient of the acquired probe information is smaller than the specified reference friction coefficient and the difference between the two is equal to or greater than a first threshold value among the acquired probe information; ,
Second specifying means for specifying a region where the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
Based on the measured friction coefficient of the probe information included in the specified area, a calculation means for calculating a partial measured friction coefficient of the specified area;
Setting means for setting the calculated partial measured friction coefficient for the specified region,
As a computer program. A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
The probe information including the position information of the probe car, the actual friction coefficient measured at the position indicated by the position information, and the weather information at the time of measuring the actual friction coefficient are associated with the road corresponding to the position information. Acquisition means for acquiring
Referring to the road information storage means, a setting means for setting a specific friction coefficient that is a specific friction coefficient corresponding to the weather information and is set in advance on a road associated with the acquired probe information;
A selection means for selecting probe information in which the measured friction coefficient of the acquired probe information is greater than the set specific friction coefficient and the difference between the two is equal to or greater than a first threshold among the acquired probe information; ,
Identification means for identifying a region where the density of the probe information is equal to or greater than a second threshold based on the position information of the selected probe information;
Estimating means for estimating the identified area as a travel performance area,
As a computer program. A computer program for controlling a server device, comprising:
Road information storage means for storing the road position information and road information including the reference friction coefficient of the road in association with each other;
A first setting means for setting a voxel on the road and setting a position of the voxel in association with the voxel;
A second setting means for setting a voxel reference friction coefficient of the set voxel with reference to the road information storage means;
Probe information including position information of the probe car, an actual friction coefficient measured at a position corresponding to the position information, and occupied area information corresponding to the occupied area in the three-dimensional space of the probe car is included in the position information. An acquisition means for acquiring in association with a corresponding road;
Based on the acquired occupation area information of the probe car, an extraction means for extracting all the voxels that overlap with the occupation area information among the set voxels;
For all the extracted voxels, replacement means for replacing the voxel reference friction coefficient of the voxel with the acquired actual friction coefficient,
As a computer program. The replacing means replaces the voxel reference friction coefficient of the voxel with the acquired actually measured friction coefficient when the number of probe information in the extracted voxel is a predetermined number or more.
The computer program according to claim 17.   The recording medium which records the computer program as described in any one of Claims 13-18.

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